(1) Field of the Invention
The present invention relates generally to a portable, self-contained, low-voltage power system for a transportable telemetry unit, and more particularly to an improved telemetry power system that provides flexibility to optimize power requirements while providing a long-lived power storage system.
(2) Background Information
The tracking and monitoring of various cargo and other shipments by industry is becoming a highly desirable service to both customers and the shipping industry. With greater use of global computer networks, the consuming public demands greater accuracy and tracking capabilities for various products and shipments. One example is the railroad industry. The capability of tracking and monitoring a particular freight car and shipment has become quite valuable to this industry.
It was for this reason that the inventor herein devised a portable self-contained track unit and GPS tracking system, which is the subject of the inventor's U.S. Pat. No. 6,339,397. One of the major features of that invention was the use of data transmissions over a wireless communications network to transmit pertinent data as to the position and condition of the railroad car and/or the associated shipment.
While there are other self-container vehicular communications systems known and used in the market, they typically use a long-life Lithium battery, or a rechargeable secondary battery, such as a Ni—MH or Li-Ion battery. While such power systems are fine for a period of time, telemetry systems typically require very long lifetimes without human intervention following installation of the power supply. In addition, the low-voltage telemetry systems of such tracking and monitoring units usually require high-current transmissions over a wireless communications channel, such as cellular or satellite communications. The high current draw of such transmissions is directly opposed to long battery life.